The range of applications for liquid crystal displays (LCDs) has increased dramatically as the characteristics of LCD displays have improved. In applications such as flat panel avionics displays and flat planel television having full color capability, it is necesssary to provide effective illumination rather than relying merely on ambient light. In flat panel displays, it is particularly desirable to have a backlight source that provides effective illumination intensity and uniformity without adding significantly to the depth dimension of the flat panel.
The use of wedge-shaped optical devices for light distribution is well known in the prior art. With such devices, light is generally injected at the large end of the wedge so that it reflects within the optical device until the critical angle of the illumination surface of the wedge is exceeded. The surfaces of the wedge may be coated or treated so that the injected light is internally reflected by all surfaces except for the emission surface which provides the illumination.
Although many types of illumination devices are known in the prior art, there is nevertheless a need for a compact LCD luminaire that provides a bright, uniform backlilght source for full color flat panel displays and that minimizes the depth dimension of the overall flat panel display.